Amateur-built DRAGONFLY accident near Helena, Montana, August 25, 1986
On August 25, 1986 at about 1:49 am local time, a amateur-built DRAGONFLY, registered N4478V, was substantially damaged in an accident near Helena, Montana (Helena Regional airport). It was a personal flight under general aviation rules (Part 91). 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 25, 1986 · about 1:49 am local time
- Place
- Helena, Montana · Helena Regional · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built DRAGONFLY
- Registration
- N4478V · no longer on the register · serial 437
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE ACFT WAS ON FINAL APCH AFTER COMPLETING A X-COUNTRY FROM BILLINGS, MT, WHEN THE ACCIDENT OCCURRED. THE PLT STATED THE ACFT WAS LOW AFTER INTERCEPTING THE VASI SO POWER WAS ADDED; HOWEVER, THE ENG DID NOT RESPOND. THE ACFT STRUCK A SMALL HILL 300 FT SHORT OF RWY. INSPECTION FOUND NO EVIDENCE OF MECHANICAL FAILURE OF THE ENGINE BUT THE UPPER CABLE FROM THROTTLE CONTROL-TO-CARBURETOR LINKAGE WAS BENT AND THE WALKING BEAM SHOWED EVIDENCE OF BINDING. ADDITIONALLY, NO EVIDENCE OF CABLE LUBRICATION WAS NOTED.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 304 hours in all; 144 in this make and model; 50 in the last 90 days; 276 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 155 hours
- Last inspection: annual inspection, August 26, 1985; 50 hours since
- Maximum gross weight: 1,150 lb
- Seats: 2
- Landing gear: fixed
- Engine: Hapi 60-2DM (piston); 0 hours total
The flight
- Departed from: BIL Billings MT
- Flight plan: none
- Runway 26, 9,000 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 290° at 7 knots
- Visibility: 40 statute miles
- Sky: scat at 7,000 ft
- Temperature: 79°F (26°C), dew point 41°F (5°C)
- Altimeter: 29.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N4478V the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.